Arka Majumdar, University of California, Berkeley

Seminar

Abstract

Understanding and engineering light-matter interactions hold the key to solving several important problems in modern society, including but not limited to high performance computing and communication. To enable optical interconnects over short distances between electrical components, and in the future even performing the whole computing process in the optical domain, the energy consumption must be decreased to several attojoules per bit. In my talk, I will describe how such attojoule optoelectronic technologies can be developed by engineering light-matter interactions at the nano-scale.

First, I will describe the coupled quantum dot (QD)-cavity system. Very strong interaction between light and matter can be achieved in this system as a result of the field localization inside sub-cubic wavelength volumes. Such strong light-matter interaction produces an optical nonlinearity that is present even at the single-photon level and is tunable at a very fast time-scale (~few picoseconds). We use this effect to perform very low power optical and electro-optical modulation. Although this system provides us with light-matter interaction at the most fundamental level and the cavities can be scaled very easily, the growth of self-assembled QDs ultimately limits the scalability of this coupled system. As a route to overcome this problem, I will describe another system: the graphene-clad photonic crystal cavity, where we have also demonstrated electro-optic modulation. With the light-matter interactions controlled at a very low energy level, these nano-photonic devices pave the way towards reaching attojoule optoelectronics.

Bio

Arka Majumdar received his B.Tech degree from Indian Institute of Technology, Kharagpur in 2007, and PhD (in Electrical Engineering) from Stanford University in 2012. He is currently a postdoctoral scholar in the Physics department, University of California, Berkley. In 2008, he held an internship in Sun Microsystems. His research interests include devices in nanophotonics, nanometallics and quantum optoelectronics with a goal to explore the fundamentals and applications of photonics in information processing. He has published more than 30 scientific papers in distinguished journals, cited more than 300 times. He is a recipient of the Gold Medal from the President of India and Stanford Graduate Fellowship.